Calculus/Limits

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Question
I need to find the limit as x-->+INF for the function f(x)=(sqrt(x^2+x)-x).  I having trouble with it thanks!

Answer
We will use the trick : √a-√b=(a-b)/(√a+√b) .
This will gives us :
√(x²+x) - x = [x²+x-x²] / [√(x²+x) + x] = x/[√(x²+x) + x]=
1/[1+√(1+ 1/x)] . Therefore :

Lim   1/[1+√(1+ 1/x)] = 1/[1+√(1+ 1/∞)] = 1/[1+√(1+0)] = ½ .
x->∞


Alon.

Calculus

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Alon Mandes

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Kind of questions I can answer : Limits, Derivatives, Integration, Implicit functions, continuousity, differentiation ,Extremum problems, Lagrange multipliers, Gradients, Surface integrals, Multi variables functions ,Multi variables Integrals,Complex variables ,Complex functions, Curves, Trajectory integrals & Vector analyse,Divergence,Rotor & word problems. Kind of question I can't answer : Economics,Combinatorics,infinite series & convergence ,Statistics & Probabilities .

Experience

1. I'm a team member of mathnerds (math site for answering questions) 2. I'm a team member in the Student's Union of the Technion, helping students who have problems in mathematics. 3. 2 years of experience as a math teacher in college. 4. I give free homework help for high school students in Mathematics & Physics. 5. I teach part time in collage the subjects : "Digital Signal Processing" , "Random Signals & Noise" , "Complex Functions".

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Hi-Tech company : GSM4VOIP ; job possition : Algorythm developer.

Education/Credentials
M.A in Mathematics & Bs.c in Electronics.

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